I don't know if this is a bug with BlogDesk or with WordPress, but when I cross post to two blogs the initial entries go up just fine. But, if I edit an existing post and re-post, the first blog will exibit the usual "do you want to replace an existing post with this one?" message and post the edited version. The second blog doesn't return that message and I end up with two posts, the original AND the modified post.

This is not a bug. If you use the command File / Edit Posts already published, you actually load this post from your blog, edit it and then repost it. There is no way to know that this post once was uploaded to several blogs. So if you want to edit & repost an article, you have to do it with every blog.

Let me try again to explain what happens. Perhaps I didn't do a very good job of explaining the first time. It is a confusing situation.
I am using the file/edit posts already published function. I edit the post and mark it to be re-uploaded to both blogs. Only one of them returns the usual "do you want to replace the existing post" question. The other will just post it as a new post, rather than replacing the old one. So, I end up with the original post and the modified one, right next to each other, since the time stamp doesn't change. I just can't figure out why BOTH blogs don't return the "do you want to replace the original post" message. Both blogs are WordPress blogs.